Natural Light from the sun and sky has a balanced spectrum, rendering colors perfectly. Most artificial bulbs emit light in only a narrow scope of the visual spectrum. Full Spectrum bulbs are not colored or coated, they are made with pure neodymium, a rare earth element mixed directly into the glass which has a natural filter to diffuse the dull yellow/green portions of the spectrum. This produces truer more natural colors and has been found to have a positive effect on how people perceive their surroundings. Great for pets and plants too! Made in the USA.